/*
 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

/**
 * Implements the UNIX crypt(3) function, based on a direct port of the
 * libc crypt function.
 *
 * <p>
 * From the crypt man page:
 * <p>
 * crypt() is the password encryption routine, based on the NBS
 * Data  Encryption  Standard,  with variations intended (among
 * other things) to frustrate use of  hardware  implementations
 * of the DES for key search.
 * <p>
 * The first argument to crypt() is  normally  a  user's  typed
 * password.   The  second  is a 2-character string chosen from
 * the set [a-zA-Z0-9./].  the  salt string is used to perturb
 * the DES algorithm in one
 * of 4096 different ways, after which the password is used  as
 * the  key  to  encrypt  repeatedly  a  constant  string.  The
 * returned value points to the encrypted password, in the same
 * alphabet as the salt.  The first two characters are the salt
 * itself.
 *
 * @author Roland Schemers
 */

package com.sun.security.auth.module;

class Crypt {

/* EXPORT DELETE START */

  private static final byte[] IP = {
      58, 50, 42, 34, 26, 18, 10, 2,
      60, 52, 44, 36, 28, 20, 12, 4,
      62, 54, 46, 38, 30, 22, 14, 6,
      64, 56, 48, 40, 32, 24, 16, 8,
      57, 49, 41, 33, 25, 17, 9, 1,
      59, 51, 43, 35, 27, 19, 11, 3,
      61, 53, 45, 37, 29, 21, 13, 5,
      63, 55, 47, 39, 31, 23, 15, 7,
  };

  private static final byte[] FP = {
      40, 8, 48, 16, 56, 24, 64, 32,
      39, 7, 47, 15, 55, 23, 63, 31,
      38, 6, 46, 14, 54, 22, 62, 30,
      37, 5, 45, 13, 53, 21, 61, 29,
      36, 4, 44, 12, 52, 20, 60, 28,
      35, 3, 43, 11, 51, 19, 59, 27,
      34, 2, 42, 10, 50, 18, 58, 26,
      33, 1, 41, 9, 49, 17, 57, 25,
  };

  private static final byte[] PC1_C = {
      57, 49, 41, 33, 25, 17, 9,
      1, 58, 50, 42, 34, 26, 18,
      10, 2, 59, 51, 43, 35, 27,
      19, 11, 3, 60, 52, 44, 36,
  };

  private static final byte[] PC1_D = {
      63, 55, 47, 39, 31, 23, 15,
      7, 62, 54, 46, 38, 30, 22,
      14, 6, 61, 53, 45, 37, 29,
      21, 13, 5, 28, 20, 12, 4,
  };

  private static final byte[] shifts = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1,};

  private static final byte[] PC2_C = {
      14, 17, 11, 24, 1, 5,
      3, 28, 15, 6, 21, 10,
      23, 19, 12, 4, 26, 8,
      16, 7, 27, 20, 13, 2,
  };

  private static final byte[] PC2_D = {
      41, 52, 31, 37, 47, 55,
      30, 40, 51, 45, 33, 48,
      44, 49, 39, 56, 34, 53,
      46, 42, 50, 36, 29, 32,
  };

  private byte[] C = new byte[28];
  private byte[] D = new byte[28];

  private byte[] KS;

  private byte[] E = new byte[48];

  private static final byte[] e2 = {
      32, 1, 2, 3, 4, 5,
      4, 5, 6, 7, 8, 9,
      8, 9, 10, 11, 12, 13,
      12, 13, 14, 15, 16, 17,
      16, 17, 18, 19, 20, 21,
      20, 21, 22, 23, 24, 25,
      24, 25, 26, 27, 28, 29,
      28, 29, 30, 31, 32, 1,
  };

  private void setkey(byte[] key) {
    int i, j, k;
    byte t;

    if (KS == null) {
      KS = new byte[16 * 48];
    }

    for (i = 0; i < 28; i++) {
      C[i] = key[PC1_C[i] - 1];
      D[i] = key[PC1_D[i] - 1];
    }
    for (i = 0; i < 16; i++) {
      for (k = 0; k < shifts[i]; k++) {
        t = C[0];
        for (j = 0; j < 28 - 1; j++) {
          C[j] = C[j + 1];
        }
        C[27] = t;
        t = D[0];
        for (j = 0; j < 28 - 1; j++) {
          D[j] = D[j + 1];
        }
        D[27] = t;
      }
      for (j = 0; j < 24; j++) {
        int index = i * 48;

        KS[index + j] = C[PC2_C[j] - 1];
        KS[index + j + 24] = D[PC2_D[j] - 28 - 1];
      }
    }
    for (i = 0; i < 48; i++) {
      E[i] = e2[i];
    }
  }


  private static final byte[][] S = {
      {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
          0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
          4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
          15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13},

      {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
          3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
          0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
          13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9},

      {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
          13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
          13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
          1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12},

      {7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
          13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
          10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
          3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14},

      {2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
          14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
          4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
          11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3},

      {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
          10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
          9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
          4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13},

      {4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
          13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
          1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
          6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12},

      {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
          1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
          7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
          2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11},
  };


  private static final byte[] P = {
      16, 7, 20, 21,
      29, 12, 28, 17,
      1, 15, 23, 26,
      5, 18, 31, 10,
      2, 8, 24, 14,
      32, 27, 3, 9,
      19, 13, 30, 6,
      22, 11, 4, 25,
  };

  private byte[] L = new byte[64];
  private byte[] tempL = new byte[32];
  private byte[] f = new byte[32];
  private byte[] preS = new byte[48];


  private void encrypt(byte[] block, int fake) {
    int i;
    int t, j, k;
    int R = 32; // &L[32]

    if (KS == null) {
      KS = new byte[16 * 48];
    }

    for (j = 0; j < 64; j++) {
      L[j] = block[IP[j] - 1];
    }
    for (i = 0; i < 16; i++) {
      int index = i * 48;

      for (j = 0; j < 32; j++) {
        tempL[j] = L[R + j];
      }
      for (j = 0; j < 48; j++) {
        preS[j] = (byte) (L[R + E[j] - 1] ^ KS[index + j]);
      }
      for (j = 0; j < 8; j++) {
        t = 6 * j;
        k = S[j][(preS[t + 0] << 5) +
            (preS[t + 1] << 3) +
            (preS[t + 2] << 2) +
            (preS[t + 3] << 1) +
            (preS[t + 4] << 0) +
            (preS[t + 5] << 4)];
        t = 4 * j;
        f[t + 0] = (byte) ((k >> 3) & 01);
        f[t + 1] = (byte) ((k >> 2) & 01);
        f[t + 2] = (byte) ((k >> 1) & 01);
        f[t + 3] = (byte) ((k >> 0) & 01);
      }
      for (j = 0; j < 32; j++) {
        L[R + j] = (byte) (L[j] ^ f[P[j] - 1]);
      }
      for (j = 0; j < 32; j++) {
        L[j] = tempL[j];
      }
    }
    for (j = 0; j < 32; j++) {
      t = L[j];
      L[j] = L[R + j];
      L[R + j] = (byte) t;
    }
    for (j = 0; j < 64; j++) {
      block[j] = L[FP[j] - 1];
    }
  }
/* EXPORT DELETE END */

  /**
   * Creates a new Crypt object for use with the crypt method.
   */

  public Crypt() {
    // does nothing at this time
    super();
  }

  /**
   * Implements the libc crypt(3) function.
   *
   * @param pw the password to "encrypt".
   * @param salt the salt to use.
   * @return A new byte[13] array that contains the encrypted password. The first two characters are
   * the salt.
   */

  public synchronized byte[] crypt(byte[] pw, byte[] salt) {
    int c, i, j, pwi;
    byte temp;
    byte[] block = new byte[66];
    byte[] iobuf = new byte[13];

/* EXPORT DELETE START */

    pwi = 0;

    for (i = 0; pwi < pw.length && i < 64; pwi++) {
      c = pw[pwi];
      for (j = 0; j < 7; j++, i++) {
        block[i] = (byte) ((c >> (6 - j)) & 01);
      }
      i++;
    }

    setkey(block);

    for (i = 0; i < 66; i++) {
      block[i] = 0;
    }

    for (i = 0; i < 2; i++) {
      c = salt[i];
      iobuf[i] = (byte) c;
      if (c > 'Z') {
        c -= 6;
      }
      if (c > '9') {
        c -= 7;
      }
      c -= '.';
      for (j = 0; j < 6; j++) {
        if (((c >> j) & 01) != 0) {
          temp = E[6 * i + j];
          E[6 * i + j] = E[6 * i + j + 24];
          E[6 * i + j + 24] = temp;
        }
      }
    }

    for (i = 0; i < 25; i++) {
      encrypt(block, 0);
    }

    for (i = 0; i < 11; i++) {
      c = 0;
      for (j = 0; j < 6; j++) {
        c <<= 1;
        c |= block[6 * i + j];
      }
      c += '.';
      if (c > '9') {
        c += 7;
      }
      if (c > 'Z') {
        c += 6;
      }
      iobuf[i + 2] = (byte) c;
    }
    //iobuf[i+2] = 0;
    if (iobuf[1] == 0) {
      iobuf[1] = iobuf[0];
    }
/* EXPORT DELETE END */
    return (iobuf);
  }

  /**
   * program to test the crypt routine.
   *
   * The first parameter is the cleartext password, the second is
   * the salt to use. The salt should be two characters from the
   * set [a-zA-Z0-9./]. Outputs the crypt result.
   *
   * @param arg command line arguments.
   */

  public static void main(String arg[]) {

    if (arg.length != 2) {
      System.err.println("usage: Crypt password salt");
      System.exit(1);
    }

    Crypt c = new Crypt();
    try {
      byte result[] = c.crypt
          (arg[0].getBytes("ISO-8859-1"), arg[1].getBytes("ISO-8859-1"));
      for (int i = 0; i < result.length; i++) {
        System.out.println(" " + i + " " + (char) result[i]);
      }
    } catch (java.io.UnsupportedEncodingException uee) {
      // cannot happen
    }
  }
}
